Mineral material, for example rock, is gained from the earth for processing by exploding or excavating. The rock can also be natural rock and gravel or construction waste. The processing is typically crushing and/or screening of material. Mobile processing plants and stationary applications are used in the processing. An excavator or wheeled loader loads the material to be processed into the processing plant's feed hopper or feed box from where a feeder moves the material to be processed into a crushing chamber of a crusher or onto a screen deck. The material to be processed may also be recyclable material such as concrete, plastic, wood, metal, bricks, or asphalt.
The mobile material processing plants are track or wheel based and may comprise means suitable for material processing such as a feed hopper, a feeder, a crusher, a screen and one or more conveyors for moving the processed material for storing or further processing.
In a known solution a feed conveyor is fixed with bolts against structures of the feed hopper wherein the feed conveyor and the feed hopper form a stiff feed entity. Manufacturing inaccuracies of the feed conveyor and of the structures being the object of the fixing complicate the fixing of the feed conveyor. The desired distance between the feed conveyor and the feed hopper is not achieved easily. Adjusting washers are used for adjusting the distance what is and difficult.
Mounting inaccuracies caused by the interface between the feed hopper and the feed conveyor complicate the operation of the feeder. In some cases a gap between a side wall of the feed hopper and a conveyor belt is too large or too small wherein the stones may between the side wall and the conveyor. If the gap between the side wall and the conveyor belt is too large material leaks through the side wall and the conveyor belt.
An object of the invention is to provide a feed apparatus in which a gap formed by a mineral material feed device and a feed box therebetween is adjustable. An object of the invention is to provide a feed apparatus in which a distance between a transport surface of a mineral material feed device and a bottom edge of a feed box is adjustable. An object of the invention is to provide a method for adjusting a distance between a mineral material feed apparatus and a feed hopper. An object of the invention is to provide a plant comprising a feed apparatus in which a distance between a transport surface of a mineral material feed device and a bottom edge of a feed box is adjustable.